Subject: Re: [PATCH] powernv:idle: Disable LOSE_FULL_CONTEXT states when stop-api fails.

From: Gautham R Shenoy <[email-masked]>
Date: Fri, 4 Aug 2017 22:30:19 +0530

On Fri, Aug 04, 2017 at 12:34:22PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <[email-masked]>
> 
> Currently, we use the opal call opal_slw_set_reg() to inform the
> Sleep-Winkle Engine (SLW) to restore the contents of some of the
> Hypervisor state on wakeup from deep idle states that lose full
> hypervisor context (characterized by the flag
> OPAL_PM_LOSE_FULL_CONTEXT).
> 
> However, the current code has a bug in that if opal_slw_set_reg()
> fails, we don't disable the use of these deep states (winkle on
> POWER8, stop4 onwards on POWER9).
> 
> This patch fixes this bug by ensuring that if programing the
> sleep-winkle engine to restore the hypervisor states in
> pnv_save_sprs_for_deep_states() fails, then we exclude such states by
> excluding their flags supported_cpuidle_states. Further, we ensure in
> the initialization of the cpuidle-powernv driver to only include those
> states whose flags are present in supported_cpuidle_states.
> 
> Fixes: 1e1601b38e6 ("powerpc/powernv/idle: Restore SPRs for deep idle
> states via stop API.")
>
Forgot to add

Reported-by: Akshay Adiga <[email-masked]>

> Signed-off-by: Gautham R. Shenoy <[email-masked]>

--
Thanks and Regards
gautham.